Peering from his trench on a ridgeline fortified with sandbags, the Kurdish commander gazed toward an Islamic State-held village next to a swath of territory recently seized from the extremist forces. Smoke wafted into the sky from natural gas burning off a well in a broad basin known as Wadi al Naft, or Valley of Oil, west of Kirkuk, Iraq's strategic northern energy hub.
"Daesh is weaker now, no doubt," said Hussein Yazdanpana, who heads an Iranian-Kurdish front-line unit, using an Arabic acronym for Islamic State. "We've heard that many of their fighters are running away," said the militiaman, who incongruously wore an American flag pocket patch — a gift from "Jack," one of the U.S. military advisors here.
While media attention has focused on Iraqi government advances north from Baghdad on the Islamic State-held city of Tikrit, the Sunni militants have also been suffering a series of significant reversals in the Kurdish north.
Unlike in the Tikrit assault — where Iran is a major partner and the U.S.-led coalition has been absent — the role of American air power is clearly evident here.
Warplanes roar unseen high in the skies overhead. The ghostly presence of abandoned, bombed-out villages — such as the flattened hamlet of Kharab al Rut, a onetime Islamic State stronghold now reduced to rubble — attests to the ferocity of the airborne assault.
U.S. military advisors are also on the scene, some outfitted in Kurdish peshmerga uniforms, though "Jack" and others encountered on the front lines declined to be interviewed.
Islamic State remains a social media superpower, still capable of churning out slick propaganda on the Internet and drawing foreign and domestic recruits.
And major challenges remain in Islamic State-controlled zones elsewhere, notably in the western Iraqi province of Anbar and in neighboring Syria, where the group emerged last year amid the chaos of a war now entering its fifth year, with no end in sight. Even in Syria, though, the extremists have suffered setbacks at the hands of Kurdish militias and government forces, including in the northern city of Kobani, along the Turkish border.
In northern Iraq, Islamic State appears increasingly under siege, its territory pinched from the north and south. There are indications that militants in Tikrit and elsewhere are pulling back to Mosul, the so-called Iraqi capital of the group's self-declared caliphate, in anticipation of a looming all-out assault by Iraqi government and allied forces.
"Absolutely, Daesh is on the run," Kirkuk Gov. Najmaldin Karim said in an interview. "Even in Hawija they have left in droves, going to Mosul," he said, referring to a notorious militant stronghold to the southwest.
Judging Islamic State's actual military strength involves considerable conjecture, given the group's secrecy and a lack of access to the vast regions of Iraq and Syria where its forces are arrayed. Hit-and-run attacks and suicide assaults — such as a series of coordinated strikes in late January in and around Kirkuk — still occur with regularity in the north and elsewhere.
But the clear impression in northern Iraq is of a militant force that is on the defensive and retrenching, facing pressure on all approaches to Mosul. The deployment of U.S.-led air power has made its once-signature armored onslaughts a thing of the past.
Even within its so-called caliphate, residents are tiring of the group's draconian rule, according to interviews with former residents of territory held by the militants. Islamic State's initial welcome in Sunni Arab towns as liberators from the Shiite-led government in Baghdad appears to have worn thin in much of the north.
"They were all right for the first two weeks after they came," said Firas Abdullah, 21, a former Hawija resident who is among thousands of displaced Sunni Arabs living in tents at a glum camp outside Kirkuk that houses mostly escapees from Islamic State rule. "But when they started stopping people from smoking, making the women wear niqab to go out, it just became too much," said Abullah, referring to the traditional Islamic face covering.
Another camp resident, Cesar Mahmoud Saleh, 31, said, "If you lived under a criminal, what would you do? We took our families and left."
Still, no one is predicting a swift defeat of Islamic State, especially as it retains its grip on Mosul, the largest city in northern Iraq and a daunting strategic obstacle. The group has placed tight controls on residents leaving the city, apparently calculating that the presence of about 800,000 civilians will limit invading forces' ability to deploy air power and heavy artillery.
With Iraqi forces advancing up the Tigris River from the south, and Kurdish-led troops tightening the noose in the north, Islamic State still seeks to project an image of defiance and invincibility, dismissing recent setbacks as strategic withdrawals.
"Congratulations for the heap of rubble in Kobani and Zumar," the group's official spokesman, Abu Mohammad Adnani, said recently in a sarcastic Web post. "Congratulations for this victory, O Pentagon."
Zumar, a town of 20,000 near the Mosul dam overrun last year by Islamic State, has indeed been left mostly destroyed and depopulated after U.S. airstrikes and the advance of Kurdish troops. It is one of many shattered towns dotting the northern Iraqi landscape. But its fall in January after fierce bombardment cleared the way for Kurdish fighters to advance toward Mosul.
Kurdish forces, backed by U.S. air power, are methodically cutting supply lines to Mosul from all directions. South of Zumar, at the strategic junction of Keske, a Kurdish detachment has effectively blocked the key route between Mosul and Tall Afar, a formerly militant-held city on the road to Islamic State terrain in Syria.
"From this spot we can disrupt supplies going to Mosul from Syria," said Capt. Ghazwan Dawood Khalo, part of a Kurdish peshmerga unit dug in behind sandbags near the Keske junction, captured in late January and now a front-line position.
"Daesh still mounts attacks, but usually with no more than 15 fighters, not like the tens of people they used to throw at us," said the captain, standing alongside a Russian-made Dushka heavy machine gun mounted on a Japanese Hino truck.
In front of the Kurdish trenches are several miles of no man's land, much of it mined. Both sides fire mortar rounds. The Kurds say they are awaiting orders to advance. But the main attack on Mosul will probably come from Iraqi government forces advancing from the south.
Islamic State's most recent losses in the north came outside Kirkuk, where Kurdish forces' aim is to tighten the noose and reduce threats to crucial oil fields and infrastructure — key objectives of Islamic State, which has made millions on illicit oil sales.
Kurdish security forces said last week that they had seized about 40 square miles of former Islamic State territory west and south of Kirkuk. Fighters said they had faced relatively little resistance from what they described as a dispirited militant force.
"We expected this fight to last nine days; instead it was over in a day," said Halo Ramashti, 30, a Kurdish Iranian fighter here on the front line along with his wife, Zohra Zahir, 23, and father-in-law, Zahir Ali.
Noting reports that militants view death at the hands of female fighters as demeaning, Zahir said, "I hope I kill many of them and they are denied being regarded as martyrs."
The three are part of a contingent of the Kurdistan Freedom Party, known as PAK, an Iranian Kurdish group opposed to Iran's leadership. About 600 party militiamen are fighting in northern Iraq against Islamic State, the group says. The battle against the Islamist militants has united often fractious Kurdish factions from Iraq, Syria, Turkey and Iran.
"Daesh is now on its last legs," Yazdanpana, the group's commander and party vice president, said Friday. "They will make their last stand in Mosul."
Special correspondent Nabih Bulos contributed to this report.